In a mobile communication system, a base station is an important component part of a mobile communication network, and is used to receive and transmit a wireless signal, so that a user equipment (UE) gets access to a wireless network.
A region such as a home environment, a workplace or a shopping mall always easily becomes a region that is covered with a relatively poor mobile signal. The problem of poor mobile signal coverage may be solved by introducing a small-sized base station such as a Micro (MICRO) base station, a Pico cell (PICO) base station, and a Femto cell (Femto) base station. For example, a Femto base station is set at home to implement indoor coverage with a family as a unit, and various types of digital subscriber lines (XDSL), fiber to the home (Fiber To The Home, FTTH) or any one of other digital subscriber access modes is used to get access to an Internet Service Provider (ISP). For an application environment such as an office building or a shopping mall, a base station regional network may be planed and designed according to requirements. For example, a MICRO base station, a PICO base station, or a Femto base station may be used to perform indoor or regional hotspot coverage; and an FTTB optical network may be used to get access to a core network, so as to provide wireless mobile signal coverage for the regional network of the office building and the shopping mall. However, for base stations that has a Time Division Duplexing (TDD) format of a communication system such as a Worldwide Interoperability for Microwave Access (WIMAX), Code Division Multiple Access (CDMA), Time Division Synchronous Code Division Multiple Access (TD-SCDMA), and Long Term Evolution (LTE), time synchronization needs to be implemented among the base stations. If it is out of time synchronization, the quality of service provided to a user is greatly affected.
In the prior art, a clock synchronization apparatus of a satellite positioning system (such as a global positioning system, a Beidou Satellite System or a Galileo system) is installed in a base station so as to implement the synchronization by using the satellite positioning system. However, the layout of a GPS feed system is limited by many conditions. For the small-sized base stations used in the region such as the home environment, the workplace, or the shopping mall, it is difficult to install a clock apparatus of the satellite positioning system for each of the base stations, and meanwhile the system networking cost is greatly increased.